regulator: cpr3-regulator: manage LDO retention mode selectively

As a safe default, LDO retention mode is disabled by the Kryo regulator
driver. Therefore, it is not necessary to manage the LDO retention
regulator when active LDO mode is not in use. Fix this by calling
cpr3_regulator_config_vreg_ldo() only when LDO mode operation is allowed.

Change-Id: Ic3e10c8b4570e3c3e01f7ceadb0f0a995b8df818
Signed-off-by: Osvaldo Banuelos <osvaldob@codeaurora.org>